Architecture: Arise Lord Rogers. Arise Battersea

Richard Rogers, everybody's favourite architect (especially Blair's) is a man with a plan or two. Plans for the Millennium, plans for the Government and his place in it and, oh yes, for a fabulous place on the Thames. By Peter Popham

"There is now a social group that wants to live in town," says Marco Goldschmied, a founding partner in Richard Rogers's firm, "in places like Manhattan this group has always existed but in London it has had to make do with flats in Bayswater... We're guilty in the post-war era of having created two classes: an underclass that went into flats, and those who've made it who live in houses, however small. By apartments we tend to mean 20s or 30s mansion blocks which were pretty grim by and large and not capable of much lift. The basic concept is too tight, too inward- looking. It's different in Switzerland or Holland or Germany or France, where apartments have always been some of the best residences. In England they have been for the relief of poverty. Basically if you'd made it you lived in a house made of bricks. And much of that culture actually remains."

Home of stray dogs, a long defunct fun fair and power station and a single Grade I listed building, Battersea is not one of the most obviously glorious corners of central London. Its dingy name was partially rehabilitated in the 1980s by an invasion of the young middle class, colonising its Victorian terraces. But now one particular Battersea address is set to become among the most desired and fashionable in London.

Battersea Thames Rise, a block of luxury flats due to begin construction next month, marks the return of Richard Rogers to residential work. In fact, with 101 flats, it will be much the largest residential building his practice has undertaken. But its significance is larger than that. It marks the return of the tower block - in a sleek, expensive new guise - to official esteem. It marks the recognition by planning authorities of what is required in terms of housing densities if "brownfield" sites are to be fully exploited, and unspoiled countryside kept that way. It is also a concrete demonstration - while the fate of his Millennium plan for Greenwich Peninsula and his scheme to redevelop the South Bank are still up in the air - of what Richard Rogers seeks to do for the river he calls, with characteristic hyperbole, "the greatest leisure park, practically, in the world."

The site of Battersea Thames Rise is fairly unprepossessing, and a good example of the haphazard and cheerless ways in which London's riverside has been developed up to now. St Mary's Church, completed in 1777, Battersea's prettiest ornament, addresses the river with typical Georgian aplomb. Everything else around it merely exploits the river or ignores it. The redundant Hovis flour mill which the Rogers block will replace fronts baldly on to the waterside, with rather less presence than a giant loaf of bread. In contrast to the elegant warehouses of Docklands further downstream, this one looks as if it was designed on the back of an envelope by the principal Miller. A housing estate next door to the east is striving by sheer willpower to move to Milton Keynes - that is the extent of its participation in the metropolitan drama. Finally, behind the site, rise the standard London sub-Corbusian tower blocks, dumped here with the standard ideological inanity. If you had wanted to abolish this place's sense of place, you could not have set about it more rigorously.

The redundant mill was the development site offered by British Land to the Richard Rogers Partnership and its team, led by Goldschmied. Doffing the cap to fashionable ideas about recycling, the architects considered converting the existing building into flats, but opted instead, wisely, to clear the site. In its place they will erect a block that will lend a desperately needed element of grandeur to this section of the river, while reaching out the hand of friendship to St Mary's Church.

Instead of coming to the water's edge like the Hovis block, Battersea Thames Rise will slant diagonally across the site. It consists of five connected blocks which rise in steps from four storeys - the block closest to the church - to 20 storeys for the block closest to the riverside. The slanting position of the block means that the present small, cramped patch of greenery between the church and the river will be expanded into a generous public park.

All the flats will have river views, and the simple, linear form of the block imparts a similar simplicity to the layouts of apartments: all the living rooms, glazed from floor to ceiling, look out on the river and the sunset in the west; while all the bedrooms, faced with terracotta tile and glass, face east. "Usually the sun sets in exactly the wrong place for where the view is," comments Rogers. "Here you get all the bedrooms on the east and all the living rooms on the west, which is just for once ideal."

The individual flats vary in size from 500 square feet (on the market for around pounds 300,000) to penthouses of up to 3,000 square feet, which will cost around pounds 3.5m each. "The penthouses are going to be magnificent," says Rogers, "rather like those penthouses you sometimes see around Paris. One or two of them are so big they practically could be artist's studios."

Rogers and Goldschmied are speaking in Rogers's own vast apartment, carved out of a handsome terraced house in Chelsea and spacious enough to have done service as a studio for Jackson Pollock. Like Marco Goldschmied, who is a product of Trieste, Harrogate, London, and Milan, Rogers with his Italian roots is a suitable exponent of apartment living; though both men are careful not to rubbish the British obsession with houses and gardens, they are in no doubt that flat living near the centre of a vibrant city like London is, almost for the first time ever, becoming a fashionable, rational choice.

So what is happening now in London is a sort of revolution, and it is under way on all sides. As companies vacate big central office blocks like the Shell Centre, both because back-up operations can now be efficiently performed out of the capital and because even 1970s office blocks are inadequate receptacles for new technology, the brave new urbanites snap them up. This newspaper's former headquarters just north of the City, remembered as a drab, dirty, characterless 1960s cornflake packet, has been reborn as The Lexington, the last word in metropolitan living. Marathon House on Marylebone Road, a cruelly minimal Miesian slab,is being recreated as luxury apartments. A swathe of offices south of St Paul's, brilliantly located for the new cultural nexus defined by the Globe Theatre and the Bankside Tate, could go the same way. There are many other examples.

So Rogers is riding a wave of the future when he says, "We very much believe that densely populated, compact cities have tremendous advantages for the people living in them, and that to have life, work and leisure all within walking distance is the ideal situation." Thousands say amen, and are endorsing him with enormous mortgages.

The view of Britain's most famous planning guru, Professor Peter Hall, is that accommodating the vast number of new households that will require housing by the year 2010 will necessitate the building of numerous new towns on greenfield sites.

The opinion of the last secretary of state for the environment, John Gummer (and Rogers believes he was an outstanding minister), was that by intensively developing brownfield sites a good part of the problem could be solved without invading virgin countryside. Hall may be right when he asserts that such developments can address only a fraction of the problem. But there is no disputing that the present rush to buy high- priced flats in the heart of London is a stunning vote of confidence in the vitality and the future of the capital.